The Structural Cell Biology (SCB) Core provides a critical tool for understanding the Structural Biology of DNA Repair (SBDR). The major challenge in the study of SBDR comes from the recognition that repair processes are coordinated through the dynamic assembly of large protein complexes. The SCB Core is specifically designed to overcome these difficulties and provide a unique resource in structural biology. The requested funding provides staff for SBDR utilization of the Structurally Integrated Biology for Life Sciences (SIBYLS) beamline at the centralized site for tackling crystallizations and structure determinations for the large macromolecular complexes known to be involved in DNA repair. The SIBYLS beamline provides tunable wavelengths for both single crystal X-ray diffraction provides the ability to determine structures from single samples, while SAXS provides a method for validation of conformational states, determination of conformational changes, and determination of solution dynamics. A key component of the SBC Core will be to provide a technological bridge between atomic resolution structures and molecular envelopes, which will bridge the gap between enzyme structures and biologically relevant, multi-component macromolecular machines. The SCB Core Aims include the development of software that addresses this problem area through the systematic and objective fitting of high resolution structures within molecular envelopes from EM single particle and SAXS experiments. The centralized Core facility will allow for the rapid dissemination of methodological developments within the Program Project in the areas of crystal generation, data collection and analysis, and structure determination. The SCB Core will provide the advanced technological tools to tackle these structures of macromolecular machines for DNA repair, and will generate insights on these multi-component systems, that cannot be understood solely through the biophysical chemistry of individual components.